If China was developing nuclear submarines for the first time in a vacuum today, copying a Russian submarine or obtaining Russian assistance would have been logical just like the path the Indians are taking today.
But all the talk of obtaining plans for the Akula makes no sense because there is no such vacuum. China developed its first nuclear submarine long after they split with the Soviet Union and was starting to be engaged with the West. Development and evolution tends to follow inertia and momentum based on what you already have and it would be very difficult to try and start something new from scratch with a design that is alien to you and components that you don't have. For example, the Russians have a design philosophy where the sail is set middle of the sub, or at least with considerable distance from the bow. Chinese submarines on the other, follow a pattern closer to some Western designs where the sail is closer to the bow. The location of the sail relative to the sub's body is fundamentally important because of the plumbing, access, and sensors and it influences how the rest of the sub is designed.